The second annual WORLD symposium will be held May 22-23, 2005 in Phoenix, AZ. In addition to the annual meeting of the Lysosomal Disease Research Network (LDRN), this symposium will provide a multidisciplinary forum to present and discuss clinical research to foster new treatment for these diseases. Specific aims are to: 1) coalesce members of the LDRN into a functional research collaboration, 2) foster interdisciplinary collaboration with the overall goal of improving knowledge of basic discoveries and clinical manifestations of these diseases; 3) identify and discuss the latest findings in the natural history of lysosomal diseases (LDs), diagnostic testing and screening, and treatment; and 4) identify areas requiring additional basic/clinical research, public policy and regulatory attention. Many of the network's constituents investigate and/or treat specific aspects of these diseases but have little exposure to work done in areas outside their current area of interest. This meeting platform promotes the sharing of basic and clinical science advances for all LDs, and provides an opportunity to discuss the related treatment outcome issues. The study and treatment of LDs pose unique challenges due to small populations of patients being dispersed over wide geographic area. Providing a forum to share information in the basic and clinical sciences will benefit both types of research and result in a more effective and efficient dissemination of knowledge, clinical guidelines, and recommendations for diagnosis, evaluation, and treatment. The 2005 meeting is organized into 3 symposia topics: 1) Current Laboratory Approaches to Understanding and Treating Lysosomal Diseases, 2) Promising Clinical Approaches in CNS Diseases, and 3) Longitudinal and Outcome Studies in CNS Diseases. The first session will provide attendees a better understanding of the pathophysiology and molecular biology of lysosomal diseases and will present new findings from a basic science perspective. Session II will identify diagnostic techniques/treatment advances in enzyme replacement therapy, hematopoietic cell transplantation, substrate depletion, and gene therapy. Session III: Longitudinal and Outcome Studies will focus on neurologic disease and response to systemic therapy. Sessions for patients and patient advocates will include educational presentations, support services, and round table discussions